Observation, Imagination, Information
There are three ways to acquire knowledge: observation, imagination, and information.
Observation (prayakṣa) is probably the most basic method. We see a car in the road, so we know it is there. Simple. Of course, it works well for simple things but sometimes its not accurate. For example, it looks like the Sun literally rises and sets, but that’s not exactly the whole truth.
Imagination (anumān) builds on observation, extrapolates it, abstracts it, and combines it in new ways. You see a bike, and you see a red car, so you can imagine a red bike. Or you see people smile when they feel happy, so when you see anyone smile you imagine they must be happy.
Imagination is great, but it can be misleading. Maybe the person isn’t happy, maybe they are just being paid to smile at customers. If there is smoke on the hill, maybe there is a fire, but maybe not.
Information (śabda) is when the imagination and observation receive guidance from an authentic source of knowledge. If a guy walks over from the hill and says, “hey man, the place is on fire over there,” then you know for sure your observation and imagination about the situation was correct.
Getting information from a third party is potentially the most powerful way of gaining knowledge, if (and its a big “if”) the third party is qualified as a genuine authority on whatever it is they are telling you.
In yoga the agents giving information are called guru and śāstra — teacher and textbook. Many practitioners, particularly Westerners, have a misconception that guru and śāstra replace observation and imagination. This is wrong. If you only hear information without imagining what you are hearing and without attempting to observe it in the real world, then everything you hear will never become more than just that — merely words to hear and perhaps repeat by rote.
When we receive information from guru and śāstra we must try to imagine and envision it in your mind, and test our images of the information against our observation of how things work in the real world. This will make us active listeners, good students.
Finally, we take our imagine of what we heard back to our teacher and say, “I listened to what you said and I think it means X, Y, Z. Is that right?” The teacher can then say, “Yes, that’s great. Good job,” or, “Well, almost, but not its a little more like W, X, Y,” or, “No, that’s all wrong, it’s like A, B, C.”
That’s the process of receiving information. Information guides the imagination and observation, it doesn’t replace it.
Just as the typical educated and uneducated modern person needs to become more aware of the enormous value of being guided by authentic information, to a similar extent many Western practitioners of Indian spirituality need to become more aware of the role that imagination and observation play in the process of receiving guidance from authentic sources.